Improved self-acting pulley-brake



Nrrnn STATns Barnier Orthop.

JOHN JOOHUM, OF BROOKLYN, NEW YORK.

lMPFtOVED SELF-ACTING PULLEY-BRAKE.

Specification forming part of Letters Patent No. dllLQ/ll@ datedNovember 29, 1864.

To all whom it may concern:

Be it known that I, JOHN JocHUM, of Brooklyn, in the county of Kings andState of New York, have invented a new' and Improved Self-ActingPulley-Brake; and l do hereby declare that the following is a full,clear, and exact description thereof, which will enable others skilledin the art to make and use the same, reference being had to theaccompanying drawings, forming part of this specification, in Which-Figure l represents a longitudinal vertical section of my invention, theline zt,- Fig. 9, indicating theplane of section. Fig.2 is an endelevation of the same. Fig. 3 is a detached view of the brake.

Similar letters of reference indicate like parts.

This invention consistin combining with au ordinary pulley-block aspherical brake attached to a spring, and applied between the sheaveandthe body of the block in such a manner that the said sheave isallowed to turn freely in one direction, butprevented from revolving inthe opposite direction, and that a pulley-block is obtained of aconvenience much superior to that of the ordinary pulley-block inhoisting, shortening sail, or other similar operations with a trilingincrease in the cost of the block.

A represents the body of a pulley-block, which is made of wood or anyother suitable material, and suspended from the rope B in the usualmanner. This block forms the bearings for the axle C of the sheave D,the circumference of which is grooved to form a secure guide for therope passing over it in the usual manner.

My self-acting brake consists of a spherical wedge, E, which is securedto a spring, F, and placed between the circumference of the sheave andthe body of the block, as clearly shown in the drawings. The spring F isso adjusted that it pulls the wedge E gently between the sheave and theblock, and it is fastened to the block by a hook, a, catching round ascrew, b, so that it can be easily unhooked whenever it may be desirableto remove the brake.

If the sheave rotates in the direction of the arrow marked on it in Fig.1 the wedge is pushed out, and the motion of the sheave takes with animperceptible obstruction; but if an attempt is made to turn the sheavein the direction opposite to the arrow marked on it the wedge E is drawnin between its circumference and the body of the block, and the sheaveis not allowed to move. The great advantage of this arrangement forpulleyblocks is apparent. In hoisting a heavy weight with an ordinarypulley-block, half the labor consists in holding` onto the rope until afresh hold can be taken, and if two men should be perfectly able toraise the weight, at least one, but generally two other men are neededto accomplish the operation of the hoisting. With my pulley-block thisextra number of men can be dispensed with. If two men are able to raisea weight, they can also hoist it readily, because the weight, onceraised,is not allowed to turn back, except if the rope is made to slideover the sheave.

' In lowering a weight my pulley-block has also great advantages. Thesheave not being allowed to turn back, causes the rope to glide over itscircumference, and one man is enabled to lower a comparatively heavyweight with little exertion. This pulley-block is ot' particularadvantage on board of vessels for all operations connected with raisingor lowering the sails, and for any other hoisting operation.

I am Well aware that a spherical brake is in use on sewing-machines toprevent the main shaft of the same being turned in the wrong direction 5but the application of such a brake to a nautical pulley-block requiresa special contrivance to adapt it to act with promptness and effect inall positions of the block.

I do not claim, broadly, the use ot' a ball as a brake for pulleys 5 butI claim- As a new article of manufacture, a nautical self-actingbrake-pulley, to be suspended by a rope, B, and consisting of the bodyA, shaft U, sheave D, ball E, and spring F, all constructed, arranged,and operating as and for the purposes herein speciiied.

JOHN JOCHUM.

Witnesses:

JAMES P. HALL, WM. F. MCNAMARA.

